Homework answers / question archive / 1) In your attempts to identify the genetic basis of inflammatory bowel disease in humans, you have DNA samples from three large unrelated families in which individuals with varying severity of the disease are found

1) In your attempts to identify the genetic basis of inflammatory bowel disease in humans, you have DNA samples from three large unrelated families in which individuals with varying severity of the disease are found

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1) In your attempts to identify the genetic basis of inflammatory bowel disease in humans, you have DNA samples from three large unrelated families in which individuals with varying severity of the disease are found. From your analysis of various SNPs, you find that the same several unlinked loci consistently show a genetic correlation with the most severe cases from all three families. Based on your observations, which of the following hypotheses best describes the genetic control of inflammatory bowel disease? A. Inflammatory bowel disease is controlled by a single autosomal dominant trait B. Inflammatory bowel disease is the result of phenocopy by the environment C. Different genes regulate the disease in the different families D. Inflammatory bowel disease is controlled by polygenic (or quantitative) traits E. Inflammatory bowel disease is controlled by a single X-linked recessive trait 2. SNP is the acronym for: A. simple nonsense peptide B. single nucleotide polymorphism C. sample in situ probe D. simple nucleotide probe 3. The pedigrees indicated here were obtained with three 13 22 13 22 unrelated families whose members express the same 12 32 12 32 12 32 completely penetrant disease caused by an autosomal dominant mutation that is ? linked at a distance of 10 CM 12 32 12 32 12 32 from a marker locus with three ? ? ? D alleles numbered 1, 2, and 3. The marker alleles present within each live genotype are indicated below the pedigree symbol. The phenotypes of the newly born labeled individuals-A, B, C, and D-are unknown What is the probability of disease expression in individual C? Leu CCU CCC CCA Pro | cco CAU His CAC CAA Gin CUA CGU CGC Arg CGA CGG CUG) CAG G e Former AGUser A 2020 2030 2030 10. Lys Catabolic pathways that break down complex substances into more usable units are usually regulated by the: AGG Arg AUU ACU | AAW) Asn AGU Ser AUC lle | ??? AAC AGC AUA |ACA The AAA AGA AUG Met ACG) AAG) GUU GCU | GAU) ASO Gau) GUC GCC GAC GGC G GUA Val GCA Ala A GAA GGA Gly Glu GUG GCG GAG GGG G U ? A. B. C. D. end products of the pathway the substrate(s) for the pathway temperature shift None of the choices is correct GAGGIU G 4. The following are members of a family exhibiting a rare autosomal dominant trait that is 100% penetrant. Blood samples were taken from each individual and analyzed by PCR amplification with two different microsatellite markers that are not linked to each other. The results are given below for each family member (coded as M-W): 6.-7. You are using positional cloning to identify a gene involved in hereditary breast cancer. You have access to a large family with many members that have developed breast cancer at an early age. After locating the region of chromosome 17 that contains the breast cancer gene, you predict 8 possible open reading frames (numbered below). M N O P Q R S T U V W Cloned region from chromosome 17 Predicted reading frames 1 2 3 4 5 6 7 8 Microsatellite 1 Which two individuals are the parents of the other 9? A. S and T B. Mand N C. Q and R D. V and W E. O and Q d Microsatellite 2 Probe A Probe C Probe D ps ps -- 1A 2B 5. Five microsatellites loci designated 1, 2, 3, 4 and 5 are known to map along chromosome 4 of corn. Each microsatellite has two alleles designated A and B. A plant breeder has obtained a strain of corn that carries a dominant F2 generation offspring pesticide-resistance gene that (from PR ps pa pa po pl ph previous experiments) is known to map somewhere along chromosome 4. The plant breeder 1B crosses this pesticide-resistance strain that is homozygous for 3B microsatellites 1A, 2B, 3A, 4B, and 5A to a pesticide-sensitive strain that is homozygous for 1B, 2A, 3B, 4A, and 5B. The F1 generation plants were allowed to self-hybridize to produce the following F2 plants: Based on these results, which microsatellite does the pesticide-resistance gene map closest to? 6. Gene expression patterns can evaluate whether a particular candidate gene is connected to the disease. To determine which tissues some of Probe B BLK BLK BLK ? BLK the candidate genes are expressed in, you perform a Northern blot analysis, the results of which are shown below. B, L, and K refer to mRNA samples derived from breast, liver, and kidney tissue, respectively. Probes A, B, C, and Dare DNA sequences from 4 of the predicted candidate genes. Which probe identifies a gene that could be considered a gene involved in breast cancer? A. A B. B C. ? D. E. none of the probes 5A 58 2A- 4A 4B 3A Based on these results, which microsatellite does the pesticide-resistance gene map closest to? A. B. C. D E. 1 2 3 4 5 11. Which of the following conditions would have neither CRP nor lacl bound to the lac operon promoter region? A. glucose B. glucose + lactose C. lactose 15. Which of the following is an RNA-based regulatory molecule that works in cis to the gene that it regulates? A. miRNA B. SRNA C lacl D riboswitch E. trpR 12. In the trp operon, the attenuator adopts different structures depending on whether the leader peptide can be translated completely or not. What would happen if you mutated the leader peptide start codon so translation could not initiate? A. Region 1 will bind to region 3 in the absence of Trp B. Region 2 would bind to region 3 to form the antiterminator loop in the presence or absence of Trp c. Region 3 will bind to region 4 and terminate transcription in the presence or absence of Trp. D. Region 3 will bind to region 1 in the presence of Trp 16. Which of the following statements is false? A. An enhancer is a type of cis-regulatory element B. The promoter is a type of cis-regulatory element C Transcription factors bind to cis-regulatory elements D. One enhancer can simultaneously regulate genes located on different chromosomes 13. Maltose utilization in E. coli requires the proteins encoded by genes in three different operons. One operon includes the genes male, malf, and malG; the second includes malk and lamB; and the genes in the third operon are malp and mal. The Malt protein is a positive regulator that regulates the expression of all three operons; expression of the malt gene itself is glucose repressible. What phenotype would you expect to result from a loss-of-function mutation in the malt gene? A. B. C D Absence of maltose-inducible expression for all three operons Constitutive expression of all three operons Absence of maltose-inducible expression for only one of the three operons Absence of tryptophan inducible expression of all three operons 17. A variety of sheep called "Belgian Texel" carry a mutation that creates increased muscle mass. The mutation was identified and found to mutate the myostatin gene such that the myostatin mRNA is now a target for a muscle-specific miRNA. Based on the general role of miRNAs in gene expression, what would you predict is the normal role for myostatin? 14. The following four E. coli partial diploids were assayed for production of the Zand Y genes (B-galactosidase and lactose permease, respectively) in the absence or presence of lactose. A. B. An inhibitor of muscle development An activator of muscle development genotype A) i-p-Oz+y+/ i* pto* z-y- B) it p-o+z+y+/ i-p+o+zty- C) i* p* oºz-y/ i*p' o* zty Dispt o+z+y:/ i pozyt Which strain will show wild-type regulation of B-galactosidase production? (use "E" for none of the above) 18. Mice usually have brown agouti fur, but a mouse geneticist has a pure-breeding white-furred strain that is homozygous for a recessive mutation. Molecular analysis shows that the mutation is a missense mutation in an exon common to three alternative splice forms of a gene expressed in hair follicles. Which of the following transgenic animals would be most useful to determine which spliced form (or forms) is affected by the mutation that results in white fur? 20. In a diploid MATalalpha yeast strain, what would be the phenotype caused by a mutation that deleted the MAT alpha 1 gene, but left MAT alpha 2 functional. (Assume that MAT a is functional.) ability to mate with MATa cells II. normal MATalalpha diploid phenotype III. ability to mate with MATa cells A. I B. 11 C. III D. I and III E. all of the above A. Construct a GFP reporter using the promoter for the identified gene. B. Use CRISPR to make a large deletion of the entire coding region of the mutant gene c C. Express a wild-type version of a cDNA for each splice form in the white mouse to see which form(s) rescue the phenotype. D Introduce the wild-type genomic allele into the mutant mouse to test for rescue of the mutant phenotype. 21. A. B. 19. You have cloned a gene that is predicted to encode a 645 amino acid protein containing a zinc finger type DNA binding domain in its carboxy-terminal 100 amino acids. You wish to determine which region, if any, of the remainder of the protein contains a transcriptional activation domain. To accomplish this you clone each of three regions (A, B and C) in-frame with the SP1 DNA binding domain. You then introduce each plasmid separately into mammalian cells that carry a GFP reporter regulated by a TATA box and an enhancer that can be recognized by SP1. The figure below shows a schematic of the predicted protein with the zinc finger domain indicated. A, B and C indicate the three regions tested for transcriptional activation; below is the relative amount of GFP measured for each construct, including the zinc finger domain used as the negative control. Which of the following statements is false regarding yeast mating? cell type specific pheromones are used mating type is genetically determined cell-type specific plasma membrane receptors are used yeast mating does not require mating-type specific genes to be transcribed signal transduction pathways are required for mating D. E. N-terminus finge C-terminus Reporter readout for transcriptional activation activity Based on these results, which region of the protein appears likely to contain a transcriptional activation domain? 22. Which of the following is false concerning the HOX gene family of mice? A. Mis-expressing a more posterially expressed Hox gene in a more anterior location will cause posteriorization of that region B. Segment-specific expression of the HOX genes results in correct vertebrae formation C. Knocking out expression of a HOX gene in one vertebra will result in transformation of that vertabra into a more anterior vertebra D The homeotic selector genes of Drosophila are not evolutionarily related to the HOX genes found in mice and humans E. A greater number of HOX genes are expressed in the posterior portion of the developing mouse spine than in the anterior portion. A A. B. C D. ? zinc finger domain